Report No 1868/B THE BIOLOGICAL EFFICIENCY OF THE PETTEN RESEARCH REACTOR BEAM ON HUMAN LYMPHOCYTES (METHODOLOGICAL APPROACH).

In this paper we present preliminary results of examination of the biological efficiency of the Petten Research Reactor mixed beam with respect to 250 kV X–rays for the induction of DNA damage and chromosomal aberrations in human lymphocytes. Human blood samples or isolated lymphocytes were irradiated by the beam from Research Reactor in ECN Petten, Netherlands and dose response relationships for the level of damage induced were investigated. In order to check any enhancement effect due to the process of boron neutron capture, chemical pretreatment with boric acid or mercaptoborane (containing boron-10 ions) was done. The estimation of the DNA damage was done with the use of a single cell gel-electrophoresis method (SCGE), to asses the frequency of chromosomal aberrations culturing of lymphocytes for the evaluation of cytogenetic damage was performed. Abnormal behavior of blood samples during a culture procedure and abnormally low metaphases frequency was noticed. During the analysis of DNA damage by SCGE assay we have also found the abnormalities in shapes and brightness of investigated comets. Part of the studied lymphocytes was bigger than others and had much bigger fraction of the DNA in tail. Ver